Safety device



July 20, 1954 R. J. KUTZLER ET AL SAFETY DEVICE Filed Sept. 1. 1949 llzs 23 25 45 5 m E w n R L m T 6 m U & m 8 I 32W W G l mo A R W 0 E 0 w w 5 JHH 74 D- 4 TL R0 E i ED N BN D 3 OAI. & 4 0 RR 5 f 5 A. 2 4 5 2 3 2 9 5 2 P 1. m l M 9 4 0 5 E I Patented July 20, 1954 tai light? SAFETY DEVICE Minn,

assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn.., a corporation of Delaware Application September 1, 1949, Serial No. 113,534

'7 Claims. 1

This invention relates to safety devices in general and, more particularly, to a safety valve or switch for controlling the flow of fuel to a furnace only upon the existence of a predetermined. safe condition, such as, the existence of a pilot flame.

One of the objects of this invention is to provide a safety device of simple construction which will provide safe delivery of fuel to a burner.

Another object of the invention is to provide a safety device which cannot be actuated to a fuel delivery position unless a predetermined safe condition exists at the burner to which the fuel flows.

Another object of the invention is to provide a manually reset safety control device, which has means for permitting a delivery of fuel to a burner only if a safe condition existsand has means for holding the elements of the device in their operating positions only so long as said condition exists.

Other objects of the invention will become apparent upon reading the following detailed description of the invention in conjunction with the accompanying drawing wherein:

Figure 1 is a vertical sectional view along the longitudinal axis of the safety device;

Figure 2 is a similar view with the elements of the device shown in the position they would assume when held in their reset positions by a U manual actuator;

Figure 3 is a similar view showing the position of the elements of the device just as they have started to move from an operating position to a safety or shut-down position; and

Figure t is a sectional view taken on line l@ of Figure 1, with portions thereof broken away.

For purpose of illustration only, the invention is shown as a gas valve having a lower casting ii, an upper casting l2, a guide plate i3, and screws l'l'extending through aligned openings in the upper casting I2 and plate l3 and screuthreaded into aligned openings in the lower casting M. It is obvious that gaskets or some suit able sealing compound may or should be provided between the engaging surfaces of the castings with the guide plate positioned therebetween.

The casting i! has a threaded inlet I5 fo receiving a fuel supply conduit and a threaded outlet it for delivering fuel to a suitable conduit leading to a fuel burner. A valve seat ll is located near the outlet end thereof. A valve 53, having a socket member l9, rests on said valve seat ll and is secured to an upwardlyextending' valve stem 2% by means of a pin 2i extendthrough the walls of said socket member is and said stem 2@.

Partition wall 22, in the lower casting ii adiacent the inlet it, forms a compartment 9.3 that is open at its upper end in line with the upper edges of the other side Walls of the casting H. A U -shaped core 2 of an electromagnet has an opening in the base thereof which receives a stud formed on the bottom portion of the partition wall 22. The stud'25 is staked over at its upper end to retain said core member firmly within the compartment. A low voltage coil 25 surrounds one of the legs of the core member and is connected by leads 2'l and 28 to conventional electrical terminal members 29 and 30, respectively. The external ends of said members 29 and 3d are connected to a thermocouple A by leads 0 and D, respectively. The thermocouple is adapted to be heated by a pilot burner B for a main burner (not shown) controlled by the safety device.

Positioned within an opening 3| in the guide plate 53 above the compartment 23, is an armature which normally rests on the upper ends of the legs of the core member 2 An upwardly es:- tending stem 33 is loosely riveted to the armature 32 in a manner well known in the art to provide a swivel connection therebetween. Stem 33 extends into a bore 34 in the upper wall of casting i2 and is guided thereby for rectilinear movement to and from the upper ends of the electromagnet core.

A channel-shaped lever'35, having forked ends, straddles the stem 33 at one of its ends and is secured to said stem 33 by means of a pivot pin 3&3. A spring 31 surrounds the stem 33 and bears against the inner end of the wall of the recess 34 and the upper surface of the lever 35, to resiliently urge the armature into engagement with the core member Z l. The other forked end of the lever 25 straddles the stem 2% of the valve it and bears against the rounded undersurfaoe of abutment member 38, suitablysecured to the valve stem 2t intermediate its ends. The stem 29 is guided for rectilinear movement by an opening 39 in the plate I3, through which the stem passes, and by a bore ii? in the top wall of casting it, which slidably receives the upper end of the stem 2B. A spring ll positioned between the of bore 4 3 and the abutment memher it, normally urges the valve it into seating engagement with the valve seat ll.

Extending through an opening 42 in the bottom. wall of casting H is a manuall operable reset plunger- 33. It also-extends through a guide opening 44 in the plate It to a point spaced slightly below the undersurface of the lever 35, intermediate its ends. Fuel is prevented from leaking through the opening 42 along the stem 43 by means of packing washers 45 and. normally resiliently held against the inner wall and outer wall, respectively, of the casting H by means of an annular shoulder or abutment member 41 and a spring pressed washer 48, respectively. An actuating knob 49 is screw-threaded or otherwise secured to the outer end of the reset plunger 43 and a spring 58 is positioned around said plunger 43 and between the knob t9 and the washer 48. It is thus seen that the spring normally urged the knob 43 and plunger 43 to its outermost position with the abutment 4'5 bearing against the packing washer 45 and the washer 43 bearing against the packing washer 46. A downwardly extending skirt portion A and a protective sleeve 5| conventionally engaging the outer surface of the skirt HA, is preferably provided to protect the reset plunger from damaging blows.

A pair of hook-like arms 35a, extending upwardly from the side walls of the channel-shaped lever 35, have laterally and upwardly inclined bearing surfaces 35b and laterall and downwardly extending surfaces 35c. This arm is adapted to cooperate with an L- shaped leaf spring 52 secured at its upper end by rivets 53 to a downwardly extending arm 54 on the upper wall of the casting |2. The leaf spring 52 bears against the arm 54 over a considerable portion of its length to limit flexing movement in a direction toward said arm but to permit flexing thereof away from said arm. The base portion 52a of the L-shaped leaf spring 52 extends laterally and is adapted to engage the surfaces 351) when said surfaces are positioned above it. As shown in Figure 1, the outer end of the portion 52a and the outer end of the surfaces 352) are either in vertical alignment or preferably, slightly overlap or intersect a plane drawn vertically past one or the other of said outer ends. It is thus seen that vertical movement of the lever 35 will cause the inclined surfaces 350 of the arms 35a to either just clear the outer end of the portion 520. or engage said outer end and flex it laterally away from the arm 54 to permit the surface 35?) to get above the portion 52a. Subsequent downward movement of the lever 35 will thus cause the ends to just clear one another or cause the surface 351) to engage the portion 52a, depending upon the particular adjustment or construction of the device. It will be understood from the following description of the operation of the device P that either arran ement is permissible for an operative device.

Operation Assuming that the safety device of this invention is installed in a heating system with the inlet 55 connected to a source of gas supply and the outlet it connected to a main burner, and the connectors 29 and 33 connected to a thermocouple being heated by a lighted pilot burner for igniting the main burner, coil 25 will be energized by the current delivered by said thermocouple and the armature 32 will be held against the end of the core 24. By pressing inwardly on the knob 49 against the bias of spring 50, the lever 35 will pivot on the pivot pin 38 in the stem 33 and raise the valve It to the position shown in Figure 2, against the bias of spring 4|. In moving to this position, the lever 35 will slide laterally across the rounded surface of the abutment 38 as well as rock thereon, due to the fact that the distance along the lever from the pivot pin 36 to the axis of the stem 20 has increased to the length of the hypotenuse of a right triangle. Likewise, the outer end of the bearing surface 35b of the arm 35a has moved upwardly and laterally on the arc of a circle to a point which gives substantial surface engagement of the surfaces 35b with the upper surface of the portion 52a of the leaf spring 52. It will be obvious that in so moving to this position, the surface 350 of the arm 35a also engaged the lower surface of the portion 52a and deflected said portion laterally to the left before the portion 52a snapped back against the arm 54 into position under the surface 35b It will be noted that in this position, the surface 35b is substantially horizontal so that the downward force on the lever 35 by the spring 4| does not impart a transverse disengaging force to the leaf spring 52 to cause disengagement thereof from the arm 3511. After the elements have reached the positions shown in Figure 2, it will be observed that the manual reset plunger may be released and returned by the spring to its lowermost position with the lever and valve remaining in their elevated positions.

Gas will then flow from the source of supply through the safety device so long as the electromagnet is energized sufliciently to hold the armature in engagement therewith. Should the pilot burner become extinguished or the size of the flame at the pilot burner become so small as to inadequately heat the thermocouple and insufficient to ignite a main burner, the current supplied to the coil 26 will be suflicient to retain the armature in engagement with the core against the forces tending to lift the armature from said core. It will be noted that in the position of the lever as shown in Figure 2, the strong spring 4| tends to rock the lever about the portion 52a of the leaf spring as a pivot against the combined forces of the weak spring 31 and. the pull of the electromagnet. The springs are so chosen that when the electromagnet is satisfactorily energized, the bias of the lighter spring 31 is sufiicient to overcome the bias of spring 4|, but, when the electromagnet is not sufficiently energized, the stronger spring 4| will overcome spring 31 and rock the lever clockwise about the portion 52a as it pivots to the position shown in Figure 3. When the lever reaches this position, the surface 35b will be at an inclination to the upper surface of portion 52a and the forces acting downwardly on the lever by springs 31 and 4| will cause a lateral component of force to be exerted by the surface 351) to the end of portion 52a and cause lateral flexing thereof to an extent necessary to permit the arm 35a to slide oif of the portion 52a and thus permit the armature and valve to assume their starting positions with the flow of fuel interrupted. It will also be observed that in moving to the position shown in Figure 3, the lever will slide transversely toward the right with respect to the valve stem 20 and abutment 38 due to the fact that the lever changes from the hypotenuse of a right triangle to a leg thereof. This lateral sliding of the lever obviously moves the outer end of the surface 35b toward the right with respect to the outer end of the portion 52a to help or completely disengage the surface 35b from said portion 52a.

With the elements of the safety device back in the position shown in Figure 1, it will be observed that any attempt to manually reset the valve to its open position, without the coil 26 being-sufficiently energized by the thermocouple,

will .be unsuccessful. Under these conditions,

inward movement of .the manual reset plunger 43 will merely pivot the lever 35 about the abut- :ment 38 on the valve stem and raise the left hand end of the lever against the bias of spring 37. This upward movement of the left hand end of the lever may or may .not cause engagement of the surface 351) with theportion 52a but, in either event, the portion52a will not retain the lever in its elevated position due to the steep angular relationship of said surface 35b with respect to the portion Site. A considerable lateral flexing force will be imparted to the spring 52, which will cause disengagement of the surfaces 35b from 52a, upon return movement of the plunger 43.

From the above description of the invention,

.it is apparent that applicants have created a new and improved safety control device which will permit the delivery of a fuel to a heating system only if it is safe to do so.

While applicants have illustrated and defined the preferred embodiment of their invention, it is readily apparent that modificationsmay be made therein without departing from the spirit of the invention. Therefore, it is to be expressly understood that the scope of the invention is to be determined solely from the appended claims.

We claim as our invention:

1. In a safety control device, a controlling member movable between a first and a second position, actuator means biased to a first normal position and'movable in one direction to a further position, condition responsive means for holding a part of said actuator means and normally in engagement therewith, means operatively connecting said actuator means and said controlling member to cause movement of said controlling member from said first to said second position when a predetermined condition exists and said actuator means is moved in said one direction from said normal position to said further position, holding means on a fixed support, and means ineluding said condition responsive means operative to permit said connecting means to transmit movement of said actuator means to said controlling member when said condition responsive means is responding to a predetermined condition and to hold said controlling member in said second position upon return movement of a portion of said actuator means.

2. A safety device comprising a valve body having an inlet and an outlet, a partition having a valve seat between said inlet and outlet, a valve movable between open and closed positions and biased toward its closed position in seating engagement with said valve seat, a condition responsive means, a member having a first portion normally engaging said condition responsive means, said first portion being held against movement when a predetermined condition exists and being freely movable when said condition does not exist, a second portion of said member engaging said valve, a first hook on said member having a laterally and outwardly inclined bearing surface, a second hook having a transversely extending bearing surface positioned and shaped to hook under the bearing surface of said first hook when said valve is in its open position and to hold said valve open when said condition exists and said inclined bearing surface is substantially parallel to said transversely extending bearing surface but unable to hold said valve open when said condif6 :tion'does not exist due to the angle assumed :by said inclined bearing surface with respect to said transversely extending bearing surface at that time, and means for moving said member to its valve open position with the hooks interengaged.

3. A condition responsive safety device which automatically moves from an operating position to a safety position when said condition is unsafe and thereafter requires resetting to return it .to its operating position, comprising, a membe) having pivoted first and second portions spaced from each other and biased in the same direction and a third intermediate portion engageable by an actuator so that when force is applied to said third portion. either said first or tion of force to saidthird portion while said secend portion is restrained from movement, condition responsive means for restraining said second portion when said condition is safe, and means -cooperating with said member to hold it in the position to which it is moved by the application of force to said third portion so long as said second portion is being restrained and after removal of said force from said third portion.

4. A condition response safety device which automatically moves from an operating position to a safety position when said condition is unsafe and thereafter requires resetting to return it to its operating position, comprising, a controller biased to a safety position and having an operating position, a member operatively associated with said controller and having a first portion which is movable in a manner to move said controller from its safety position to its operating position upon application of force to said member while a second portion of said member is being restrained against movement, said first portion of said member remaining in its safety position upon application of force to said memher when said second portion is unrestrained, condition responsive means for restraining movement of the second portion of said member when said condition is safe whereby application of force to said member results in movement of said controller to its operating position, and means for holding said member in said operating position upon the removal of said force.

5. In combination, a fluid supply conduit, a biased closed valve for controlling fluid flow through said conduit, a lever having a first portion for actuating said valve to its open position said lever having a bearing surface at an acute angle to the levers longitudinal axis, condition responsive means for holding a third portion of said lever against movement, means for actuating said lever about said third portion as a pivot to open said valve, and latch means engageable with said bearing surface on said lever to hold said valve open when said third portion is being held and to release said valve to its closed position when said third portion is released by its holding means during the normal operation of said valve permitting said lever to pivot about said latch means to a position where the lever slips off of said latch means to permit said first and third portions to return to their initial positions.

6. In a device of the class described, the combination comprising a support, control means, means biasing said control means to its inoperating position, condition responsive means, connecting means between said control means and said condition responsive means, holding means cooperable with said connecting means for holding said control means in its operating position when said condition responsive means is immovable due to the existence of a predetermined condition, said holding means having a latch thereon that isincapable of holding said control means in its operative position when said condition responsive means is permitted to move under the bias of said biiasing means due to the nonexistence of said condition, and means for moving said connecting means and control means to their operating positions when said condition exists, said moving means being incapable of moving said control means against said biasing means to its operating position when said condition does not exist.

7. A condition responsive safety device which automatically moves from an operating position to a safety position when said condition is unsafe and thereafter requires resetting to return it to its operating position, comprising, a member having a first or safety position, said member including first and second portions separately biased toward their first positions and spaced from each other and a third intermediate portion where force is applied so that said first or second portion will act as a pivot about which the other rotates to move said member to second or third positions respectively depending upon which of said first or second portions has the greater restraint against movement, a controller normally biased to its safety position and associated with said member for movement from its safety position to its operating position upon movement of said member to its second position by application of force to said third intermediate portion while said first portion is restrained from movement by a force greater than the bias on said second portion, condition responsive means for exerting such a greater restraining force upon said first portion when said condition is safe, and means releasably engaging said member intermediate its ends to hold it in the position to which it is moved by the application of force to said third intermediate position while said first portion is being restrained and after removal of said force from said third intermediate portion, said last-named means including latching means which remain latched when said member is in its second position but unlatches when said member moves out of its second position upon release of said first portion.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,245,834 Sparrow June 17, 1941 2,258,811 Ray Oct. 14, 1941 2,303,672 Wantz Dec. 1, 1942 2,333,261 Mantz Nov. 2, 1943 2,475,430 Kronmiller July 5, 1949 2,481,265 Van Denberg Sept. 6, 1949 2,504,048 Rice Apr. 11, 1950 2,533,982 Weber et a1. Dec. '12, 1950 

